Aggregate of pressure medium cylinders

ABSTRACT

A device for an aggregate for pressure-medium cylinders is described, comprised of means for counter-balancing of forces in the use of the aggregate, and which is characterised by a central section comprising end support bodies ( 13, 14 ), and at least two channel sections ( 11, 12 ) preferably pipe-formed, aranged side by side and with the longtudinal axes running in parallel (and ring-formed in parallel when several channel sections are used), and comprising an opening alternately to each side along the longitudinal axis, as at least a first ( 23 ) and at least a second ( 24 ) pressure-medium cylinders are guided with their piston rods first into the channel sections ( 11, 12 ) and the piston rods ( 15, 16 ) are secured to their respective ends (gables) at a fastening point ( 17, 18 ), and that the piston rod is kept stationary, and the cylinder part of the presure-medium cylinder is movable in its rigid mouning in the channel sections ( 11, 12 ).

[0001] The present invention relates to pressure-medium cylinders built together to an aggregate of at least two cylinders arranged next to each other with their longitudinal axis mutually parallel and with the piston rods of the cylinders turned in the opposite axial directions. The invention relates to a device of an aggregate of pressure-medium cylinders as described in the introduction in claim 1.

[0002] Such aggregates are known, as in Norwegian Patent No. 306.424 for example, and give double the stroke-length of a conventional cylinder when it is based on the same cylinder length. The resultant force is the sum of the force delivered by the individual cylinder cell.

[0003] An aggregate comprising two pressure-medium cylinders will have a distance (a) between the centre-lines of the piston rods, and two oppositely directed and equally large forces (K), which will make up a force-pair with a moment equal to K×a. Slides on the outside of the aggregate have been fitted to absorb this momentum.

[0004] An aggregate comprising four pressure-medium cylinders with the cylinders arranged in the form of a ring and with two cylinders with piston rods diametrically opposite each other, turned in an axial direction, and the other two arranged in the same way with the piston rods turned in the opposite axial direction, will have a weakness for bending and buckling. The weakness occurs ninety degrees (90°) displaced between the two ends of the aggregate. The weakness will be directed diametrically in one direction on the one side of the aggregate, while on the other side the weakness for bending is 90 degrees to the first direction.

[0005] With the present invention one aims to solve both the problems pointed out above.

[0006] An aggregate consisting of pressure-medium cylinders according to the invention is characterised by a mid-section comprising end support bodies and at least two channel sections, preferably pipe-formed, arranged side by side and with the longitudinal axis running in parallel, (and ring-formed in parallel in the case of several channel sections), and comprises an opening alternating to each side along the longitudinal axis, with at least a first, and at least a second pressure-medium cylinder being guided with the piston rods at first into the channel sections, and the piston rods are fixed to their respective ends (gables) at a fixing-point, and that the piston rod is held tightly and the cylinder part of the pressure-medium cylinder is moveable in its rigid mounting in the channel section.

[0007] According to a preferred embodiment, the mid-section consists of two gable ends and at least two pipes are rigidly secured to the gable ends, and the pipes are arranged next to each other with their longitudinal axes running in parallel, (and ring-formed in parallel in the case of several pipes) and have pipe openings alternating to each side along the longitudinal axis.

[0008] Preferred embodiments of the invention appear from the dependent claims.

[0009] The penetration of the pipes takes place in both end pieces, and such that each pipe has one penetration, and that they point in their own axial direction. A pressure-medium cylinder is guided into the one pipe with the piston rod first, and the piston rod is secured to the end piece opposite the penetration. The other pressure-medium cylinder is conducted into the other pipe, now from the opposite side, with the piston rod first, and the piston rod is secured to the other end-piece. The pipes in the mid-section will now be guiding and supporting the cylinder pipes of the pressure-medium cylinders that will move while the piston rods will be stationary.

[0010] In many cases the cylinder pipes will have a sufficiently large moment of resistance to absorb the momentum we have indicated above, and this will be a useful construction.

[0011] In some cases this will not be good enough, and one aims with the present invention to solve this problem. An aggregate according to the invention is arranged as described above with the same mid-section, and the same placing of at least two pressure-medium cylinders, but with pipe-formed piston rods, and with the piston rods being conducted through the end piece it is secured to. A stuffing box is fitted in the end-piece and a pipe is guided into the piston rod with the one end and is guided into the plate for the eye of the cylinder opposite with the other end and secured there. The same is carried out with the other piston rod and the other eye plate.

[0012] One can now lead the pressure-medium into the eye plates, and one can arrange a surface of attack for the pressure-medium and in this way suspend the moment effects. In addition, this will increase the force that the cylinder can deliver.

[0013] Another solution according to the present invention is that it is a shaft which is guided into the hollow piston rod, and that at the end of this shaft is a piston and that this piston, by way of the shaft, transfers force to the eye plate and in this way counteracts the momentum effect.

[0014] An aggregate according to the invention includes a pair of pressure-medium cylinders arranged side by side with the longitudinal axes running mutually in parallel, and with the cylinder parts of the pressure-driven medium rigidly connected to each other, and the piston rods being turned in mutually opposite axial directions.

[0015] The piston rods are pipe-formed, and the pipe goes through the piston. A hole is drilled in the rear gable of each cylinder, and grooves are made for sealants in connection is with this. Pipes are led into the hollow piston rods, one from each side, and secured to the eye plates at the other end. Oil is then fed through the pipe and will exert a force against the eye plate and counteract the moment. Here, one will also be able to have a rod with a piston at the end to exert a force against the eye plate through the rod.

[0016] In another case in which one uses two or more pairs of cylinders, the aggregate is further characterised in that a mid-section consisting of two gable ends, and in this case four pipes which at the one end are secured to the gable end without going through it and at the other end go through a hole drilled in the gable end and is secured to this. The centre lines of the pipes are running mutually in parallel, and they are arranged in the form of a ring with two openings diametrically opposite each other, turned in an axial direction, and the other pair arranged in the same way with the openings turned in the opposite axial direction. Two pressure-medium cylinders are led into the pipes with the piston rods first, and the piston rods are secured to the gable end. The same is carried out with the other two cylinders from the opposite side. The pipes in the mid-section will now be for guiding and mounting of the cylinder pipe parts of the cylinders, which will move, and will give a steady and good mounting. This will remedy in the situation we described initially, in which we had a situation with an aggregate with four cylinders where the cylinder sections were rigidly secured together and where the piston rods went out in pairs in their own axial direction. Here, we got a weakness for bending with ninety degrees difference in the two cylinder pipe-ends.

[0017] Further features of the present invention will appear from the subsequent description with reference to the enclosed drawings, in which:

[0018] FIGS. 1A-1B show in two different length sections a first embodiment of an aggregate according to the invention which comprises of a mid-section in which two cylinder pipes are arranged to move in mutually opposite directions.

[0019]FIGS. 1C and 1D show the aggregate according to FIGS. 1A-B in end section viewed from the two opposite ends.

[0020]FIG. 2 shows, according to another embodiment example a further developed embodiment of the invention according to FIG. 1 in which there are pipe-formed piston rods, and where pipes are led from the eye plates and into the pipe-formed piston rods. Here, a cutaway through the centre section is also shown.

[0021]FIG. 2 A shows the aggregate according to FIG. 2 in a horizontal projection plan, and with a cutaway along the centre line shown in a sectional elevation.

[0022]FIG. 3 shows in a third embodiment example an aggregate according to the invention with a pair of mutually parallel pressure-medium cylinders with mutually opposite directed piston rods. The piston rods are pipe-formed and pipes run from the eye plates and into the pipe-formed piston rods.

[0023]FIG. 4 shows a fourth embodiment example, an aggregate according to the invention of two pairs of mutually parallel pressure-medium cylinders, the cylinder parts of which are arranged in pairs in opposite directions. A mid-section provides a fastening point for the piston rods and mounting for the movable cylinder parts.

[0024] The FIGS. 4A and 4B show the aggregate according to FIG. 4 viewed from the two opposite ends.

[0025] In FIGS. 1A,B (see also FIG. 2) an aggregate is shown with a mid-section 10, consisting of two pipes 11 and 12, which are rigidly connected to two gable ends 13 and 14. The pipes 11,12 are led through an adapted boring for each gable end 13,14 and then led up to the other gable end 14,13 respectively, and then secured at both ends. The pipes are arranged next to each other and with their longitudinal axes running in parallel. A pair of cylinders 23,24 (FIG. 2) are fitted to the centre section with their respective piston rods 15 and 16 secured to their own gable end at the points 17 and 18, and the cylinder parts 23 and 24 being movably mounted in the pipes 11 and 12. Thus the piston rods 15,16 remain stationary, and the cylinder parts 23,24 move in their mounting in the centre section. At the extreme ends of each cylinder part an eye plate 19 and 20 is fastened, and the eyes 21 and 22 are secured to these.

[0026] The piston rods 15,16 comprise a pipe-formed material so that oil can flow from the pressure side in the cylinder and out into the piston rods, as holes 40,42 are drilled in the gable end plates in the securing points for the piston rods 15,16 and a stuffing box 27,28 (FIG. 3) is provided, with pipes 29,30 being led into the piston rods 15,16 and secured in a boring 44,46 in the respective eye plates 19,20 that leads to a chamber 48,50 in the eye plates, and that the pipes 29,30 can be replaced with rods, which in the one end are secured in the eye plates and which have a piston fitted in the other end, and rod and piston are placed inside the hollow piston rods.

[0027] This construction offers significant resistance to bending and will withstand moderate loads and thus be useful in many cases.

[0028]FIG. 2A shows a further development of the solution in FIG. 1, in which one has equipped the aggregate with pipe-formed piston rods 25,26. Holes for the piston rods are drilled in the gable ends, and sealing rings 27,28 are fitted in the gable ends. The pipes 29,30 are then fitted with the one end in the pipe-formed piston rods 25,26, and fastened in a boring in the eye plates 19 and 20. Oil with system pressure will now counteract the moment effects, and could also cancel it.

[0029] The pipes 29 and 30 can be replaced with rods, and pistons can be fitted to the one end that is led into the hollow piston rods 25,26. This will also give strength to counteract a lopsided load and moment.

[0030] This means that a mid-section 10′ (see FIG. 4), with gable ends 13′,14′ one or more pairs of first 11′,11″, and second 12′,12″, pipes are arranged in the form of a ring with their longitudinal axes running in parallel, are rigidly connected to the gable ends 13′,14′ and have diametrically in pairs their pipe openings to each side of the longitudinal axis. One or more pairs of the first 23′,23″ and second 24′,24″ cylinder parts of the pressure-medium cylinders are fitted in pairs in the pipe openings in the mid-section with the piston rods secured to the gable ends 13′,14″, and the movable cylinder parts protruding from their pipe racks diametrically extending in pairs in their respective direction of the longitudinal axis.

[0031]FIG. 3 shows an aggregate 31 with a pair of mutually parallel pressure-medium cylinders with mutually opposite directed piston rods. The cylinder pipes 32 and 33 are secured at both ends to two gable ends 34 and 35. These gable ends contain all the necessary mounting and sealing means, and have borings in both ends of the cylinder pipe. Pipe-formed piston rods 36,37 are fitted, and pipes 42,43 are led from the eye plates 38 and 39 through the boring in the gable ends 34 and 35 and into the resepctive piston rods 36,37. As pipe and piston rod will separate during large piston strokes, a telescopic guiding device 40 and 41 must be fitted which is pulled out of the pipe and guides the parts together again.

[0032] This means that at least a first 32 and at least a second 33 pressure-medium cylinders are arranged next to each other with their longitudinal axes running mutually in parallel, that the cylinder parts of the cylinders are rigidly connected to each other in pairs, and that said first and second piston rods 36,37 of the cylinders are faced in pairs in mutually opposite axial directions with the piston rods 36,37 being pipe-formed, and a hole is drilled and sealants are arranged at both gable ends 34,35 as pipes 42,43 are led into the hollow piston rods, and these are secured to the eye plates 38,39 and that an oil chamber is arranged in the eye plates, and that the pipes become disengaged at large piston strokes, so that there are arranged an extendable guiding device 40,41 which leads the parts together again.

[0033]FIG. 4 shows an aggregate with two mutually parallel pressure-medium cylinders secured and mounted in a centre section, with stationary piston rods and movable cylinders, as shown in FIG. 1. It appears from FIGS. 4a and 4 b that such an aggregate is weak against buckling influences on the one side while it is strong in another direction, while it is the reverse for an influence in a direction displaced 90 degrees.

[0034] This problem can to a large extent be solved for most loads by arranging the aggregate as shown in FIG. 1, and if there are large loads, one can use solutions as shown in FIG. 2. 

1. Device at an aggregate of pressure-medium cylinders, comprising means for counterbalancing of forces at the use of the aggregate, characterised in that a central section comprising end support means (13,14), and at least two channel sections (11,12), preferably pipe-formed arranged side by side and with the longitudinal axes running in parallel, (and ring-formed parallel with several channel sections) and comprising an opening alternately to each side along the longitudinal axis, as at least a first (23), and at least a second (24) pressure-medium cylinder are led with the piston rods first into the channel sections (11,12), and the piston rods (15,16) are secured to their respective ends (gables) at a fastening point (17,18), and that the piston rods are kept stationary and the cylinder part of the pressure-medium cylinder is movable in its rigid mounting in the channel sections (11,12).
 2. Device according to claim 1, characterised in that the mid-section comprises gable ends (13,14) and at least two pipes (11,12) being rigidly secured to the gable ends, and the pipes (11,12) being arranged next to each other with the longitudinal axes running in parallel, (and ring-formed in parallel when using more pipes), and has pipe openings alternately to each side along the longitudinal axis.
 3. Device according to any of claims 1-2, characterised in that the piston rods (15,16) comprise a pipe-formed material, so that oil can flow from the pressure side in the cylinder and out into the piston rods, as there are holes drilled in the gable end plates in the fastening-points for the piston rods (17,18), and a stuffing box (27,28) is arranged, and pipes (29,30) being led into the piston rods (15,16) and secured in a boring in the eye plates (19,20) which lead to a chamber in the eye plates, and that the pipes (29,30) can be replaced with rods, which in the one end are secured to the eye plate, and which have a piston fitted in the other end, and the rod and the piston are arranged inside the hollow piston rods.
 4. Device according to any of the preceding claims, characterised in that a central section 10′ with gable ends (13′,14′), one or more pairs of the first (11′,11″) and second (12′,12″) pipes are arranged in the form of a ring with their longitudinal axes running in parallel, are rigidly connected to the gable ends (13′,14′) and have diametrical pipe openings in pairs to each side of the longitudinal axis, one or several pairs of first (23′,23″) and second (24′,24″) cylinder parts of the pressure-medium cylinder are fitted in pairs in the pipe openings in the mid-section with the piston ends secured to the gable ends (13′,14′), and the movable cylinder parts protruding diametrically out from their pipe bearings in pairs extending in their respective direction of the longitudinal axis.
 5. An aggregate of pressure-medium cylinders, characterised in that at least a first (32), and at least a second (33) pressure-medium cylinders are arranged next to each other, with their longitudinal axes running mutually in parallel, that the cylinder parts of the cylinders are rigidly connected in pairs to each other, and that the piston rods (36,37) of said first and second cylinder, are turned in pairs in mutually opposite axial directions, with the piston rods (36,37) being pipe-formed, and that holes are drilled, and seals inserted in both gable ends (34,35), as pipes (42,43) are led into the hollow piston rods, and these are secured to the eye plates (38,39), and that an oil chamber is arranged in the eye plates, and that the pipes become disengaged at large piston strokes, so that an extending guiding device (40,41) is arranged which leads the parts together again. 